county appraiser reclassified my unit mix two weeks before closing and now the loan type changed

i'm under contract on a triplex in akron, ohio, purchase price $312,000, and i was set to close with an fha loan on the 15th. two weeks out, the county auditor updated the parcel record and reclassified it from a three-unit residential to a two-unit with a commercial accessory space, because the bottom unit has a separate exterior entrance and a half-bath that apparently crosses some threshold i didn't know existed. my lender won't do fha on a mixed-use classification. they came back with a conventional option but now i need 15% down instead of 3.5%, which is $46,800 versus $10,920. i don't have the difference sitting around. seller is willing to extend to june 1 but won't renegotiate price. the bottom unit was renting for $875 and i was going to live in the middle. the whole reason the payment worked was the fha structure and that $875 counted in full. i've called two other lenders this week and both of them see the same classification problem. i'm trying to figure out if there's a path to getting the county record corrected before june 1, or if that's just not realistic in ohio in eight weeks.